Blow-out magnet.



Patented July 22, I902.

w. B. POTTER. BLOW-OUT MAGNET.

(Application filed Feb. 28, 1901 Rgnewed Apr. 28, 1902.)

2 Sheets-Sheet 1,

(N0 Modej.)

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William B Potter" TNE Norms PETERS ca, PHoYuuTHo" WASHINGTON. n c.

No. 705,|38. v Patented July 22, I902.

W. B. POTTER. v

' BLOW-OUT MAGNET.

(Application filed Feb. 28. 1901. Renewed Apr. 23, 1902.) (No Model. 2 Sheets-Sheet 2.

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Witnesses:

Inventor.

5 William B. Potter 2 Y Atty.

UNITED STATES rt-ion.

WILLIAM B. POTTER, OF SCHENECTADY, NEW YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

BLOW OUT MAG NET.

SPECIFICATION forming part of Letters Patent No. 705,138, dated July 22, 1902.

Original application filed October 11, 1397, Serial No. 654.793. Divided and this application filed February 28, 1901.

. Renewed April 23, 1902A Serial No. 104,322. (No model.)

To atZZ whom it may concern:

Be it known that I, WILLIAM B. POTTER, a citizen of the United States, residing at Schenectady, county of Schenectady, State of New York, have invented certain new and useful Improvements in Blow-Out Magnets, (Case No. 2,103,) of which the following is a specification.

This is a division of application Serial No.

IO 654,793, filed October 11, 1897, for improvements in electric railways.

The invention herein relates more particularly to improvements in blow-out magnets in general and to the application of these mag- I 5 nets to electric switches in general, and especially to electromagnetic switches used in connection with sectional electric railways.

Blow-out magnets have heretofore been constructed with soft-iron or steel cores and pole-pieces in order to obtain increased permeability and consequent highermagnetization. I have discovered that when the coils of such magnets are connected in circuits through which the current-flow is liableto z 5 considerable variance the blow-out is not efficient to dissipate small destructive arcs current, the magnetic blow-out is not efficient to blow out the are at the switch-contacts 40 when the switch is opened. It is evident that such conditions might exist in any electric circuit; but I have found the application of my invention to be especially useful in connection with railways of this class. In order to overcome this"difficulty, I have constructed the blow out magnets with case-hardened iron or cast-steel cores and pole-pieces in order that the magnets may have a large amount of residual magnetism and coercive force-- invention.

that is, so that they will be more or less perman ent in character. In case of leakage from one surface conductor to another and consequent small current-flow through the coil of the blow-out magnet the permanent magnet will cooperate with the energizing-coil to blow out arcs at the switch-contacts which would not otherwise be dissipated if the ordinary form of blow-out were used. Although this result is accomplished by the sacrifice of some little permeability of the magnet, nevertheless this will be compensated for because the permanent magnet will cooperate with the energizing-coil when the full line-current is flowing through the coil. Moreover, since the coil is frequently energized, as by the repeat- 6 ed closing of the electromagnetic switches, the cores and pole-pieces of the magnet will be prevented from magnetic deterioration.

Of the drawings,'Figure 1 is a plan of an electromagnetic switch embodying a blow-out 7o magnet constructed in accordance with my Fig. 2 is a vertical section of the same. Fig. 3 is a side elevation of the same, more clearly showing the relative location of the blow-out magnet. Fig. 4: is a plan of the switch-piece support of the electromagnetic switch. Fig. 5 is a diagram of the connections of a sectional-conductor railway, showing the connections of the blow-out magnet and switch-actuating magnet; and Fig. 6 is a detail showing the arrangement of the insu- 1ating-base and blow-out coil.

' The switch-actuating electromagnet is described in detail in the application above referredto and of which this is a division, and

it is necessary here to only indicate its general features. The energizing-coil A of this magnet is retained in an iron casing B, which is suitably secured, as by screws, to the upper portion of an insulating-base D. The bottom on of this case serves normally as a support for the movable magnet-core G, which'depends through a hole in the insulating-base and carries the movable switch-contacts at its lower end. The stationary switclncontactsE E are preferably metallic and are secured to the lower side of the insulating-base D by screws 6, which extend through its upper side and have their heads in countersunk holes. The blow-out magnet N is located above the insulating-base D adjacent to the casing B and is supported in that position by its polepieces 0 O, which are curved to extend around the insulating-base, where they are enlarged and secured to the insulating-base by screws d on opposite sides of the switchcontact E, which is the contact which is adapted to be connected by one of the screws e with the feeder 2, Fig. 5, through the blowout magnet-coil N. The ends of the polepieces 0 O are provided with depending projections N between which are located the contact E and the movable carbon-contact J, which is carried by the movable support shown'in Fig. 4.

The core of the magnet N may be of steel and the pole-pieces O and O of case-hardened cast-iron. However, any suitable metal may be used for either, providing the result is increased permanency and coercive force. The pole-pieces are suitably insulated from the core and from the switch-contacts.

In Fig. 5 the surface contacts or conductorsections R R are shown as connected to the feeder 2 through the electromagnetic switch H. l his switch is normally held open by gravity, but is lifted into engagement with the stationary contacts E, E, and E by means of the coil A, which is connected between the surface contact U and the return to the generator. It might happen after a car-collector had passed from the sections R and B that there would be a leakage of current across from either of these contacts to the contact U, and hence to the return through the coil A. This leakage-current might be sufficient to hold the switch H closed for a time, but might be discontinued to permit the switch to open. In such case an arc would be formed at the feeder-contact E; but as the leakagecurrent is relatively small with respect to the normal line-current the blow-out coil N, which is connected in series between the feeder and the contact E, would not have sufficient strength to blow out this are if the blow-out magnet were constructed in the ordinary way. According to my invention, however, by the cooperation of the portion of the magnet which is permanent with the energizing-coil the are at the switch-contact E will beeffectively blown out, even with the limited flow of leakage-current through the energizing-coil.

What I claim as new, and desire to secure by Letters Patent of the United States, is-

1. The combination with a circuit in which the current strength is subject to considerable variance, of a switch therein, any arcing at which it may be highly desirable to avoid, a permanent magnet of hard iron having a large amount of residual magnetism and coercive force, and an energizing-coil for the magnet which is connected in the circuit, whereby the permanent magnet cooperates with the coil, to blow out small destructive arcs at the switch when a small current is flowing through the circuit.

2 In an electric railway, the combination with the feeder, of branch connections from the feeder, a sectional conductor having its sections connected to the feeder branches, electromagnetic switches in the branches, the current-flow through which switches varies considerably from various reasons, magnets having a large amount of residual magnetism and coercive force, to remain permanent under adverse service conditions, and energizing-coils for the magnets, which coils are connected in the feeder branches, whereby the permanent magnets cooperate with the coils, to blow out small destructive arcs at the switches when only a small current is flowing through the feeder branches.

3. In an electric switch, the combination of fixed and moving contacts with an arc-disruptive means, comprising a permanent blowoutmagnet having an energizing-coil, the ar rangement being such that the field of the permanent magnet is employed to disrupt the arcs formed at times when the current flow ing in the energizing-coil is insufficient to create a strong field, and a combined field, due to the permanent magnet and energizing-coil, for disrupting the arcs formed at times when larger currents are flowing in the system.

4. In a switch, the combination with an insulating-base, of'a switch-contact secured to the lower side of the base, and a blow-out magnet supported above the base by its polepieces, which are extended around said base on opposite sides of said contact, and are secured to the lower side of the base.

5. In a switch, the combination with an insulating-base, of a switch-contact secured to the lower side of the base by a screw extending from the upper side of the base, and a blow-out magnet having one end of its coil adapted to be connected to said contact by said screw.

6. In a switch, the combination withan insulating-base, of a switch-contact secured to the lower side of the base, and a blow-out magnet supported above said base by its polepieces, which are extended around the base and secured thereto on opposite sides of said contact, said pole-pieces having depending projections which extend down below the contact.

7. In an electric railway, the combination with the feeder, of conductor-sections, electromagnetic switches which may have a variable flow of current from their coils, for connecting the feeder with said sections, magnets having a large amount of residual magnetism and coercive force, and energizing coils for said magnets which are connected between the feeder and the feeder-contacts of said electromagnetic switches, said permanent magnets cooperating with said magnetcoils to blow out small destructive arcs at the switch-contacts when a relatively small curvided with an energizing-coil arranged to to rent is flowing through the blow-out magnetblow out the ares formed at one pair of concoils. tacts.

8. In an electromagnetically operated In Witness whereof I have hereunto set my 5 switch, the combination of a magnet, fixed hand this 25th day of February, 1901.

terminals angularly displaced, moving con- WILLIAM B. POTTER. tacts similarly displaced, a support to which VVitn-esses: the moving contacts are secured controlled BENJAMIN B. HULL,

by the magnet, and a permanent magnet pro- EDWARD WILLIAMS, Sr. 

